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post #1 of (permalink) Old 09-16-2005, 08:59 AM
kaiser sosa
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more power from my 4 cyl YJ

I have "acquired" a '95 YJ 4 cyl w/ auto trans.

My main question is this.....what would you recommend for getting more power? a header worth the $$$?

Here's what I am shooting for:

1. Good driver (would like to get over 65 MPH without having to put it on a trailer) but a jeep that I can hunt with this year.

Here's the plan:

A. Keep tires @ 30''...maybe 31'' and add a 1'' shackle ..then a 1'' body lift if needed.

B. Keep the remainder of it basically stock (I am on a very small budget.

My current logic tells me that it isn't worth the PIA or $$$to change engines (it's possible that I could swap in a rebuilt 6 should bolt up to the existing auto trans). If I can't get what I need out of the 4 banger, I would be better off selling it and looking for a Jeep w/ a better powerplant.

Any opinions?

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post #2 of (permalink) Old 09-16-2005, 09:17 AM
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Re: more power from my 4 cyl YJ

"acquired" ? are you implying you stole it???

stick with 30's if you are looking for a driver...

get a throttle body form a 4.0L, that makes the most dif. can be had from junk yards or

K&N filter...lil difference, but still some....

exhaust? do it if you need a new one.....
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post #3 of (permalink) Old 09-16-2005, 09:28 AM
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Re: more power from my 4 cyl YJ

Don't spend a dime on after market stuff that promises more HP. The TB swap is cheap, and does help the engine gulp more air... but that's about all and usually only in the upper RPM's. You can almost do that by removing the restrictor in the air tube.

So, look at the price for the modification. Then look at the payback ratio of Dollar to Horse Power. You'll find you're not the winner!

Then look at all the stuff you want to put on the engine to increase the HP and add up the price. You'd be spending a whole lot of money for a whole lot of nothin' but disappointment.

Now, sell the Jeep and buy one with a 6 cylinder engine, or learn to live with the 4 angry squirrels you've got under the hood.

You'll be money ahead.
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post #4 of (permalink) Old 09-16-2005, 11:29 AM
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Re: more power from my 4 cyl YJ

Sosa...your asking the right questions....both Leve and Greg are right....Besides the cost of a header, you have to modify the exhaust pipes....headers do nothing for low and mid range and are high maintenance....except for the TBI, there is nothing you can really do....


Keep the tires small....larger tires have a direct effect on effective gearing, hence, going up 2 sizes can make it feel like your pulling a 10 ton trailer. If you do want larger tires, then regear, that will get your performance back where you want it.

Air Pressure - Keep proper air pressure in the tires and it will roll easier.

Reduce wind resisance....not much you can do about the shape....but if you start adding all those bolt on "make it look cool" goodies, you will only slow it down. Don't waste money or effort on the body lift...increases wind resistance and does not really do much for you.

With the price of gas....I think you are just fine right now with that 4 banger...tough engine....and it's fuel injected...low maintenace.

Good Luck
post #5 of (permalink) Old 09-16-2005, 02:30 PM
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Re: more power from my 4 cyl YJ

Don't waste your money on motor parts unless your swapping in a bigger one. My parents have a 4 banger auto on 31" ltb's and the thing is gutless on paved roads, getting it up to 60 or 65 is a chore and when you hit a hill you loose all that speed you just gained. Now you ask what would make this jeep more fun and capable on the highway with out a motor swap, gears. It has 3.73's and if it had 4.10's or 4.56's the thing would move a ton better. Once you put the jeep in 4 low it's an animal but 4hi it's a gutless pig.

JP did an article where i think they put on a cold air intake, 4.0 throttle body, header, cat back and gained some where around 10hp and it probably cost them near $1500 in parts, just not worth it for the results.
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post #6 of (permalink) Old 09-16-2005, 06:32 PM
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Re: more power from my 4 cyl YJ

4 cylinder and 6 cylinder have different bellhousings IIRC.
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post #7 of (permalink) Old 09-16-2005, 11:22 PM
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Re: more power from my 4 cyl YJ

You could always gear it down some more too. If you put 4.88s in it you still be able to get 65.
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post #8 of (permalink) Old 09-17-2005, 12:10 AM
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Re: more power from my 4 cyl YJ

I have the same Issue, my 95 has a 4banger auto and rolls on 33's (slowly), I bought it that way, and plan to regear soon, I do drive it on the freeway and can hit 65 or 70 but its a p.i.t.a. sometimes but the 33's are still in excellant shape, and it works ok off road so until the money becomes available for a regear ill live with it.

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post #9 of (permalink) Old 09-17-2005, 12:36 PM
kaiser sosa
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Re: more power from my 4 cyl YJ

Thanks for the info.

By "acquired", I mean that it only cost me $50. I won it in a pool during last years Superbowl game. 100 people put in $50, and I got lucky.

After all of the research done and your input, I will give it a tune-up, put gas in it, go w/ 30'' tires, get a frame for the used soft top that I picked up for it and just live w/ it on the highway but enjoy it in the woods.

Thanks again for all of the info.
post #10 of (permalink) Old 09-17-2005, 01:26 PM
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Re: more power from my 4 cyl YJ

Now your thinking.....just run it like it is, and enjoy it until you have to repair. I would suggest going with 31's max on a 4 cyl. Having bigger tires, would require gearing $$$$$.
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